Anthropogenic chemical cues can alter the swimming behaviour of juvenile stages of a temperate fish Carlos Díaz-Gil a, b, * , Lucy Cotgrove c , Sarah Louise Smee c , David Sim  on-Otegui a , Hilmar Hinz a , Amalia Grau b , Miquel Palmer a , Ignacio A. Catal  an a a Instituto Mediterr aneo de Estudios Avanzados, IMEDEA (CSIC-UIB), C/Miquel Marqu es 21, 07190, Esporles, Illes Balears, Spain b Laboratori d'Investigacions Marines i Aqüicultura, LIMIA (Balearic Government), C/Eng. Gabriel Roca 69, 07157, Port d'Andratx, Illes Balears, Spain c School of Ocean Sciences, College of Natural Sciences, Bangor University, Menai Bridge, Anglesey, LL59 5AB, UK article info Article history: Received 13 October 2016 Received in revised form 17 November 2016 Accepted 27 November 2016 Available online 6 January 2017 Keywords: Chemical cues Sparus aurata Behaviour Sunscreen pollution abstract Human pressure on coastal areas is affecting essential ecosystems including fish nursery habitats. Among these anthropogenic uses, the seasonal increment in the pressure due to leisure activities such as coastal tourism and yachting is an important environmental stressor in many coastal zones. These pressures may elicit understudied impacts due to, for example, sunscreens or other seasonal pollutants. The island of Majorca, northwest Mediterranean Sea, experiences one of the highest number of tourist visits per capita in the world, thus the surrounding coastal habitat is subject to high anthropogenic seasonal stress. Studies on early stages of fishes have observed responses to coastal chemical cues for the selection or avoidance of habitats. However, the potential interferences of human impacts on these signals are largely unknown. A choice chamber was used to determine water type preference and behaviour in naïve settled juvenile gilt-head sea bream (Sparus aurata), a temperate species of commercial interest. Fish were tested individually for behavioural changes with respect to water types from potential beneficial habitats, such as seawater with extract of the endemic seagrass Posidonia oceanica, anthropogenically influenced habitats such as water extracted from a commercial and recreational harbour and seawater mixed with sunscreen at concentrations observed in coastal waters. Using a Bayesian approach, we investigated a) water type preference; b) mean speed; and c) variance in the movement (as an indicator of burst swimming activity, or “sprint” behaviour) as behavioural descriptors with respect to water type. Fish spent similar percentage of time in treatment and control water types. However, movement descriptors showed that fish in sunscreen water moved slower (98.43% probability of being slower) and performed fewer sprints (90.1% probability of having less burst in speed) compared to control water. Less evident increases in sprints were observed in harbour water (73.56% more sprints), and seagrass (79.03% more) in comparison to control water. When seagrass water was tested against harbour water, the latter elicited a higher number of sprints (91.66% increase). We show that juvenile gilt-head seabream are able to react to a selection of naturally occurring chemically different odourscapes, including the increasingly important presence of sunscreen products, and provide a plausible interpretation of the observed behavioural patterns. © 2017 Elsevier Ltd. All rights reserved. 1. Introduction Approximately half the world's population lives within 100 km of the coast, a figure likely to double by 2025. The Mediterranean Sea is undergoing a ‘‘basin-wide urbanisation process”, with more than two-thirds of the Mediterranean coastline already developed (Benoit and Comeau, 2005). Moreover, coastal tourism and leisure activities are becoming the largest and most rapidly expanding activity in the world; in the Mediterranean there is expected to be 264 million foreign coastal visitors by 2030, compared to 98 million in 1995 (Predosanu et al., 2011). Consequently, this further in- creases the seasonal pressure on coastal areas that already suffer from a high degree of urbanisation, such as farms, residential pre- mises, harbours, marinas and other industrial assets (Miller, 1993). * Corresponding author. Instituto Mediterr aneo de Estudios Avanzados, IMEDEA (CSIC-UIB), C/Miquel Marqu es 21, 07190, Esporles, Illes Balears, Spain. E-mail address: cdiaz@imedea.uib-csic.es (C. Díaz-Gil). Contents lists available at ScienceDirect Marine Environmental Research journal homepage: www.elsevier.com/locate/marenvrev http://dx.doi.org/10.1016/j.marenvres.2016.11.009 0141-1136/© 2017 Elsevier Ltd. All rights reserved. Marine Environmental Research 125 (2017) 34e41